TOKYO -- Katsuya Takanashi, a 56-year-old disgraced securities executive, is an unlikely symbol of the new Japan.

Mr. Takanashi once sat on the board of Nomura Securities Co., the most powerful brokerage firm in Japan. But three years ago, he was forced to resign, along with other Nomura directors, to take responsibility for a series of scandals. He rotated in discreet obscurity through a series of jobs at Nomura-related companies, a common fate for fallen executives here -- until last October, that is, when he joined Wit...